Kaposi sarcoma (KS) is an opportunistic disease in HIV patients and the most common cancer associated with AIDS worldwide. Identified a decade ago as the causative agent of KS, the human herpes virus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpes virus (KSHV), has a 125 kb genome encoding approximately 90 gene products. Many of these gene products allow the virus to evade the human immune system. KS primarily affects AIDS patients, but it can also occur in non-HIV-infected individuals and presents as classical, endemic or post-transplant forms. HHV-8 also causes two other rare B-cell cancers, primary effusion lymphoma (PEL) and multicentric Castleman disease (MCD), which are primarily found in HIV-infected or other immunosupressed patients.
Currently, there is a need for sensitive and specific testing to identify HHV-8 infected individuals, especially among potential blood and/or organ donors. Low viral loads in blood limit the sensitivity and thus usefulness of PCR-based approaches. Alternatively, a variety of serological tests have been tried to detect antibodies to HHV-8 proteins and diagnose infection using various target antigens, all with limited success.